Concentration of ores.



of the invention,such as will enable othersf naynon'zo F. Bacon, or zezr'rssunen. 'PENNSEELVANIA, assxeuon TO METALS nnoovnnv COMPANY, or new storm, s. A. CORPOBATION or meme.

union;

ooncnnrnarron on em. I

No Drawing.

To all whom it may concern Be it known that I, RAYMOND F. Bacon,

and useful Improvements in"Concentration of Ores; and I do hereby declare the follou ing to be a full, clear, and exact descrlption skilled in the art to which it appertains to make and usethe same. I This invention relates to the concentration of ores and to the separation of metal constituents thereof from each otherand from associated gangue, by a procedure which involves a fractional separation of the metal constituents and conversion thereof into a form suitable for flotation, and by a subsequent flotation treatment.

In the common flotation processes ofc0n centratinglow grade sulfid ores, the processinvolves an indiscriminate separation of sulfid from gangue; Where the sultid particles are themselves superficially oxidized or coated with an oxid film, it has been common practice toieifect the flotation in the presence of an acid which will dissolve and thus remove such oxid films and leave the sulfid particlessuitable for flotation, vThis solution of oxid constituents,however; re-

sults in a loss of metal 'values,. fwhich' can only .be recovered by a subsequent treatment, and which are oftenvpresent in such dilute solution as to make recovery impracticable. I

It has heretofore been proposed-to ellect a selective separation of sulfid ores by first subjecting the ores to'apartial roast to convert some of the constituents intoaform unsuited to flotation-and then floating the unchanged sulfids fromthe thus changed constituents. Such proposals are open to the,

objection that a clean separation is not possible with many ores since it is difficult to completely convert certain sulfids without partially converting them all, and to theextent that those sulfids are converted which it is desired to retain as sullids, their separation is prevented; Oxidized constituents re: main \vlth the tailings and are not -sepa rated; Moreover, in many ores'the sulfide are so intimately blended that it is impossible to eil'ect a clean separation of said nonsulfids from each other, or to effect a, S8180" specification oif Letters Patent. i Patented Sept. 12, 1916, I

. v a Application filed November 10, 1915,. Serial No. 60,697.

tive oxidation or deadening of said inconstituents only. l i

It has also been proposed to convert oxid ore's into sulfids by treatment with hydrogen sulfid or soluble sulfids, and: by thereafter subjecting the ore to flotation; but sucliprocedures also involve an indiscriminate sepa-,

ration of all sulfids formed' from the gangue. Wherethe oxid or other non-sulfidconstituents are present intimately blended with each other and with the gangue, the suliidizedore retains the constituents in a corresponding state of combination.

It has also been proposed to separate oxidized. lead and zinc compounds in suspen- 551011.111 the presence of an acid by-treatment with sulfureted hydrogen or a soluble suliid, thereby coating only the lead with a layerof sulfid without converting the oxi dizedzinc into sulfid, the zinc oxid not-being affected by the sulfid in an acid solution; the thus partially sulfidized ore being subsequently subjected to flotation. With many ores, such a proposal is not practicable because of the intimate-blending of the lead and zinc with each other and with the gangue, even in a finely crushed condition. Where the lead and zinc are thus blended, the particles will remain physically combined even after partial sulfidization and a clear separation will be thus precluded. Moreover, to the extent that the gangue is physically attached to the oxid or sulfid particles, it will, either be removed with such particlesor will tion thereof.

All of the various procedurcsreferred to above involve a preliminary crushing to effeet a physical separation of the gangue from the ore. Where the ores areofsuch a nature that such physical separation cannot he. efiected' by cruslimg the separation is to that extent prevented and prejudiced.

Similarly, the proposals to eil'eet selective from each other or from oxid constituents are SUlOJQCttO the limitation that where these gether in the same'finely divided particles,

their separation is not practicable for the reason that the treated particles still reprevent the desired separw' separation of different sulfid constituents constituents are intimately combinedtotain such constituents in a similar sta'teof all an improvement on such prior processes and proposals, overcoming many of the disadvantages indicated above, and enabling in addition new and improved re" sulfid constituents from gangue, as have been referred to, the process of the present invention involves a selective or fractional separation of metal constituents from each other and from the gangue which will be more clear and sharp, and which can be applied to ores incapable of satisfactory concentration by methods heretofore proposed. lVliile all oi the proposals referred to above depend primarily upon the physical se aration of the ore from the gangue and 0 dift'crentorc constituents from each other, the

process of the present invention enables a separation of metal constituents from each other and from the gangue to be efiected Where such physical separation by crushing is not possible. 7 i

The process of the present invention com: prisesa preliminary treatment of the ores 'to convert part or all of the metal constituents into a soluble form, where these constituents are not already soluble and a sub sequent treatment of the soluble constituents with a suitable acid to effect solution thereof. Subsequently the dissolved metal constituents are fractionally precipitated within the pulp as sulfids, and finally the precipitated sulfide are separated from the ore pulp by flotation.

The solution and precipitation processes of obtaining metals from their ores, heretofore practised, involve dissolving the metal values, filtering the dissolved values from the ore pulp and washing and draining the ore pulp to complete the separation of the dissolved constituents. Such processes are practicable with relatively concentrated ores, but with low grade ores having large amounts of gangue material, the separation of the dissolved constituents from the ore pulp by filtering and by subsequent washing is a slow and imperfect procedure. Where silicate ores are treated, more or less silicic acid is often set free, of a more or less gelatinous nature, which further impedes the filtration of the orc pulp hen the solutions are finally ob tained, they are usually more or less dilute, requiring the handling of large volumes of liquid from which the metal values must be precipitated after preliminary purification. i ls distinguished from such solution and precipitatirm processes where filtration followed by precipitation and a second filtration is necessary, the process-of the present invention comprises dissolving and precipitating the metal values within the pulp as sullids, and (fleeting the separation of the thus prr-icipitated sulfids by flotation meth- {possible to effect substantially complete solution of certain metal constituents, or of all metal constituents, from the gangue even where the crushed "ore particles contain the gangue intimately blended with the ore.

The procem of the present invention further comprises a fractional precipitation and separation by flotation of the dissolved metal values, whereby the metal constitu cats can be fractionally separated from each other.

Z'Lhe ores which can be treated according to the present invention may be either of a sulfid orot an oxid or other non-sulfid nature. Theprocess is of more or less general application to ores containing different metal constituents, particillarly metal constituents which form acid insoluble sulfigls Where the orcs are already of an oxidized nature, they can be treated Without further preliminary preparation than a suitable crushing. This crushing, moreover, need not be as fine and complete as has heretofore been necessary with flotation processes inasmuch as, by the present process, the metal constituents can be effectively sepa' 'ated without being entirely separated physically from associated gangue.

In treating sulfid ores, a preliminary roast, either partial or complete, is often necessary or advanta 'eous. Thus with zinc blend ores containiug lead, the lead and zinc sulfids are so intimately combined and blended with each other that it is impossible to efi'ect physical separation by any crushing procedure. In order to eil'ect separation of such ores, it is necessary to dissolve the Zinc and thus separate it from the lead. Where the zinc sulfid is soluble directly in dilute acid, it can be thus dissolved without preliminarily roasting but it may, however, be more advantageous to subject the ore to a preliminary roast and thus loosen the texture of the ore particles so that they can be more readilv extracted and dissolved.

The invention will be described more in detail in connection with the treati'nent of certain specific ores, from which the nature and advantages of the invention will more clearly appear. It will be understood, however, that the invention is of more general application and that it is illustrated by, but is not limited to, these specific illustrations of its application.

In treating copper sulfid ores containing iron pyrites, or in treating mixed copper and iron sulfid ores such as chalcopyrite. with which iron pyrites is usually present, the ore is subjected to a preliminary roast at a red heat or at a suitable temperature to decompose the iron sulfid and. leave the copper, in

the lead sulfate has not been completely sulfidizerhwill he floated and separated from the ore pulp while the zinc and iron will remain in solution. The zinc can be subsequently recovered by precipitation as sulfid 7 acid insoluble sulfide have been precipitated and removed, the excess acid should be neutralized. By then treating the ore pulp with an alkali sulfid such as sodium sulfid or with an alkalihe earth sulfid or sulfhy drate, such as calcium sulfbydrate, the zinc or nickel can then be precipitated and its flotation thereafter effected. After the precipitation of the zinc, any excess hydrogen sulfid or soluble sulfid should advanta geously be neutralized and the pulp rendered faintly acid to promote the flotation process.

Instead of using sulfuric acid, sulfur dioxid or mixtures of sulfur dioxid with sulfur trioxid can be used in a more or less similar manner. By using, sulfur dioxid as the extracting agent for forming the solutions of the metals within the pulp, and by subsequently treating with hydrogen sulfid, not only will the acid insoluble metal sulfids be precipitated, but colloidal sulfur will also be formed.

In my companion application Serial No. 36,698, filed June 28, 1915. l have described and claimed the treatment of non-sulfid ores, either simultaneously or successivcly with sulfur dioaid and hydrogen sulfid, and thereby effecting a sulfidizing of the ore and the formation of colloidal sulfur within the ore pulp. In said companion application, I have also described and claimed the fraw tional 01. selective separation of metal con- StltilBIlilSlfIOlll each other by such colloidal sulfur process. The claims of said appli a tion, however, are limited to a procedure wherein such colloidal sulfur is formed and made use of for effecting separation; while in the present application the claims are drawn generically to the fractional or selective separation by the use of any suitable acid, and specifically to the use of sulfuric acid, as distinguished from the use of sulfur dioxid. ii

In separating, the precipitated sulfids from the ore pulp and gangue by flotation, the pulpv may be subjected to aeration, with agitation, and the flotation thereby effected,

or a small amount of oil can be beaten into the pulp togetherfwith the air, and a froth thus obtained, In either case, the flotation is materially irnlioved by the presence of the precipitatednrulfids which are of a more or less colloidal nature than the naturally occurring sulfid constituhnts, of the ore.

From the above description it "will be seen that the invention is of more or less general application, both to the treatment of completcly oxidized ores and to the treatment of ores only partially oxidized. In all cases the procedure involves'aqpreliminary solution of acid soluble metal constituents to form a preliminary solution thereof within the ore pulp, and the subsequent fractional precipitation of acid insoluble sulfids within the pulp by treatment with hydrogen sulfid or other soluble suliid in the presence of a suitable excess of acid. Inasmuch as hydrogen sulfid is readily obtainable from sullid ores by a reducing roast, or from sulfur dioxid by heating with a suitable reducing gas; and inasmuch as sulfuric acid can also be readily obtainable from smelter fumes by oxidation; it will be seen that the reagents employed are simple and readily produced in amounts necessary for commercial operations, from the suliid ores themselves.

It will also be seen that the process is capable of many different applications in the art, and accordingly that many variations and modifications can be made in the invention as described, Without departing from its spirit and scope, as set forth in the ac.- l-ompanying claims.

What- I claim is:

1. The method of effecting; the separation of metal constituents forming acid soluble and acid insoluble sullids from each other and from associated gung'ue, which comprises dissolving the acid soluble constituents of the one with an acid and thereby forming a solution of the same in the presence of the ganguc, thereafter effecting a fractional precipitation of metal constitu cuts forming acid insoluble sulfids from those forming acid soluble sullids by treatment with hydrogen sullid in the presence of a suitable excess of acid, and finally subjet-ting the rcsulting mixture to a flotation treatment; substantially as described.

2. The method of cllecting the separation of metal constituents forming acid soluble and acid insoluble sullids from each other 126 and from associated ganguc, which comprises dissolving the acid soluble constituents of the ore with an acid and thereby forming a solution of the same in the presence of the gangue, thereafter effecting c.1215 fractional precipitation of metal constituents forming acid insoluble sulfids from those forming acid soluble sulfids by treatment with hydrogen sulfid in the presence of. a suitable excess of acid, subjecting the lat espoused" I resulting mixture to a flotation treatment, subsequently precipitating as sulfids metal constituents forming water insolublesuliids by neutralizing the excess acid and treating and other metal constituentsbf the ore with an acid and thereby form ng a solution of,

the same in the presence of the gangne, 1.5a thereafter effecting a fractional precipita tion ofthe copper as sulfid by treatment with hydrogen sulfid .in the presence of a suitable excess of acid; and finally subjecting the resulting mixture to aflotation treatzoment; substantially as described.

' 4. The method of effecting the separation of zinc fromnletals forming acid insoluble sulfids and from associated gangue, which comprises dlssolvlng the zinc and other acid the same in the presence of the gangue;

thereafter effecting a fractional precipitation of the metal constituents forming acid ment'with hydrogen sulfid in the presence of a suitable excess of acid, subjecting the resulting mixture to a flotation treatment, subsequently precipitating the zinc as sulfid by neutralizing the excess acid and treating with a suitable sulfid; and finally separating the zinc sulfid' bya further flotation treatment; substantially as described.

5. The method of efiecting the separation of sulfid ores ,containingiron pyrites to prises subjecting such ore to a preliminary partial roast and thereby converting the iron pyrites', together with part of the other metalconstituents, into an acid soluble form, dissolving such acid soluble constituents of the ore with an acid and thereby forming a solution of the same in the presence of the gangue and from-the acid insoluble metal constituents, thereafter effecting a fractional precipitation of metal constituents forming acid insoluble su lfids, as .sulfids Without precipitatingthe iron, by treatment with hydrogen sulfid in themes 55 once of a suitable excess of acid, and finally subjecting the resulting mixture to a flotation treatment; substantially as described.

6. The method ofefi'ecting the separation of lead and zinc from each other and from associated gangne in sulfid ores, which comprises roasting theme to convert the zinc into a soluble form, dissolving the zinc and .iother acid. soluble constituents with an acid andlthereby forming a solution of the same in the presence of the gangue'and from the soluble metal constituents of the ore with insoluble snlfids from the zinc by treat-'- 'gether with other metalsulfids, which coming 'awfractional precipitation and converqsion ot the lead, and other metal constituents forming acidinsoluble sulfide, into sulfiils by treatment with hydrogen sulfid "inthe presence of a si'iitablcexcess of acid, subjectingthersulting mixture to a flotaition treatment, subsequently precipitating the Zinc as sulfid, and again subjectingfthe mixture to a flotation treatment; substantiully as described. i b i 1 7; The method of eifectifig the separation andacid insoluble constitit dnts fromeach other and from associated gangue, which comprises dissolving the acid soluble'constituents of the ore with dilute sulfuric acid and thereby forming a solution of the saine of metal constituents forming acid soluble All! the presence ot'thc gangue, thereafter reflecting a fractional precipitation of metal constituents forming acid insoluble sulfids fromlthose forming acid soluble sulfids by treatment with hydrogen sulfid in. the presence of a suitable excess'of sulfuric acid, and finally subjecting the resulting mixture to a flotation treatment; substantially as described. c *4 8. Themetlrod of effecting the separation -of zinc from metals forming acid insoluble sulfids and from associated gangu'e, which comprises dissolving'the Zinc and other acid soluble metal constituents of the orewith sulfuricacid and thereby forming a solu tionof the same in the presence of the gangue, thereafter effecting a fractional precipitation "of. the metal constituents forming acidinsoluble sulfids from the zinc by treatment with hydrogen .sulfid in the presnce of a, suitable excess of sulfuric acid, subjecting the resulting mixture to a flotation treatment, subsequently precipitating thezinc as sulfid by neutralizing the excess acid and treating with" asuitable sulfid; and finally separating the zinc sulfid by a further flotation treatment; substantially as A described.

9., The method of effecting the separation of lead and zinc from, each other and from associated gangne in sulfid ores, which comprises sub ecting the ore to a sulfatizmg roast, dissolving the zinc and other acid,

thereby forming a solution of the same in soluble constituents with sulfuric acid and the presence of the gangue and from the insoluble constituents, thereafter effecting a fractional precipitation and conversion of the lead, and" other metal constituents forming acid insoluble sulfids, into 'sulfids, by treatment with hydrogen sulfid in the'presence of a suitable excess of acid until the lead sulfate has been sufficiently sulfidized to enable its flotation, and finally subjecting the resulting mixture to a flotation treatment; substantially as described;

10. The. method of effecting the separation oflead and copper from zinc and from :ISSOUIzItLti gangue 1n sulfid ore continuing mm pyrites. which comprises roasting the ore to convert the iron pyrites together with more or less of the other metal eonetituents, into an acid soluble fornndiseclving such :ieid soluble constituents of the etc with an acid and thereby forming H eolution of the same in the presence of the gnngguc and from the acid insoluble metal constituents. thereafter effecting a i'l'm'tirmul precipitation and conversion of ture. .M

RAYMOND F. BACON. 

